Snow and ice on the ground
In the Day Microphysics RGB, the red colour from snow and ice on the earth surface results from a strong reflection of short wave solar radiation channel (VIS0.8). The more homogenous the snow/ice cover is, the brighter the colour will be. Snow and ice on mountains will therefore be depicted in a stronger reddish colour than snow on ground often disrupted by vegetation.
MSG channels IR3.9 and IR10.8 contribute less to the satellite measured radiation since the first is sensitive to snow and ice crystals (dark in IR3.9) and the latter shows dark blue shades because of the rather warm snow surface.
The Day Microphysics RGB from early March 2013 shows snow over large parts of the Baltic States, Belorussia and the Ukraine. The red colour is less intense and changes towards magenta.